opencv动态显示图像像素值

也比较简单，参考了网上的代码：

#include "cv.h"
#include "highgui.h"

void mouseHandler(int event, int x, int y, int flags, void* param)
{
IplImage* img0, * img1;
CvFont font;
uchar* ptr;
char label[20];

img0 = (IplImage*) param;
img1 = cvCloneImage(img0);

cvInitFont(&font, CV_FONT_HERSHEY_PLAIN, .8, .8, 0, 1, 8);

if (event == CV_EVENT_LBUTTONDOWN)
{
/* 读取像素 */
ptr = cvPtr2D(img1, y, x, NULL);

/*
* 显示像素值，注意是BGR
*/
sprintf(label, "(%d, %d, %d)", ptr[0], ptr[1], ptr[2]);

cvRectangle(
img1,
cvPoint(x, y - 12),
cvPoint(x + 100, y + 4),
CV_RGB(255, 0, 0),
CV_FILLED,
8, 0
);

cvPutText(
img1,
label,
cvPoint(x, y),
&font,
CV_RGB(255, 255, 0)
);

cvShowImage("img", img1);
}
}

int main()
{
IplImage* img = cvLoadImage("E:\\分类数据1\\5273-分类1.bmp", 1);

/* always check */
assert(img);

/* create a window and install mouse handler */
cvNamedWindow("img", 1);
cvSetMouseCallback("img", mouseHandler, (void*)img);

cvShowImage("img", img);

cvWaitKey(0);

/* be tidy */
cvDestroyAllWindows();
cvReleaseImage(&img);

return 0;
}